Experimental evaluation for ballistic materials

Experimental work is based on the data obtained from ballistic tests and is an integral part of soft body armour engineering. From a research point of view, results from the experimental tests and observations not only directly indicate the performance and usability of materials in ballistic applications, but provide empirical data to test the validity of the theories that are put forward in this field as well. This section will list the methods and approaches adopted to study fabric response and evaluate its performance upon ballistic impact. 

Schmidt et alT used a pair of high speed cameras to record the dynamic deformation, showing shape and strain details of a fabric upon ballistic impact The information obtained is used to validate the FE model in LS-DYNA and to quantily the transverse deflection. Nurick used light rays emitted from a silicon photovoltaic 

Many techniques have been used to measure the velocity of a projectile. The most widely used systems are instantaneous, discrete techniques such as sensors or chronographs. Impact or residual velocity of a projectile is calculated from the distance between two sensors divided by the time taken by the projectile flying between the sensors. Sensors currently employed in the ballistic range include light-emitting diodes, laser beams, thin wires, or infrared beam. Impact and residual velocities obtained from the rig are used to calculate the projectile kinetic energy loss AE  

Where m is the mass of the projectile in kg, and are striking and residual velocities of the projectile in m/s respectively. The energy loss due to air friction could be obtained by performing the test without any samples. Energy absorbed by sample target could therefore be worked out. 

Type n annour that is new and unworn shall be tested with 9nun FMJ RN bullets with a specified mass of 8.0 g (124 gr) and a velocity of 398 m/s 9.1 m/s (1305 ft/s 30 ft/s) and with. 357 Magnum jacketed soft point (JSP) bullets with a specified mass of 10.2 g (158gr) and a velocity of 436m/s 9.1 m/s (1430ft/s 30ft/s). 

---